Sighting apparatus for anti-aircraft guns



@fafman A. DAWSON` AND s. T. BUCKHAM.. SIGHTING APPARATUS FOR ANTI-AIRCRAFT GUNS.

APPLICATION FILED 'JULY 7, 19|?.

Patented Nov. 30, 1920.

3 SHEETS-SHEET I:

1 ,360,730. Patented Nov. 30, 1920.

3 SHEETS-SHEET 2.

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A. T. DAWSON AND G. T. BUCKHAM. SIGHTING APPARATUS FO' ANTI-AIRCRAFT GUNS.

APPLICATION man 1u.L Y 1. |911.

1,360,730., Patented Nov. 30, 1920.

@SHEETS-SHEET 3.

erzirs immersioni iastate/'isere UNITED sTArEs OFFICE.

ARTHUR TREVGR DAV/'SON AND GEORGE THOMAS BUCKHAM, 0F WESTMINSTER,

LONDON, ENGLAND, ASSIGNORS TO 'VICKERS` LIMITED, 0F WESTMINSTER, EN Gr- LAND.

SIGHTING- APPARATUS FOR ANTI-AIRCRAFT GUNS.

Specification of Letters Patent.

Patented Nov. 30, 1920.

Application mea :any 7, 1917. serial No. 179,267.

To all whom t may concer/a Be it known that we, Sir ARTHUR TREVOR DAWSON, knight, and Sir GEORGE THOMAS BUOKHAM, knight, both subjects of the King of Great Britain, residing at Vickers House, Broadway, Westminster, in the county of London, England, have invented certain new and useful Improvements in or Relating to Sighting Apparatus for Anti-Aircraft Guns, of which the Jfollowing is a speciiication.

This invention relates to sighting apparatus for anti-aircraft guns in which means are provided for correcting the angle of tangent elevation during the elevation and depression of the gun. In such sighting apparatus it has been suggested to vary the angle of tangent elevation by means of a circular guide which can be adjusted into different degrees of eccentricity with respect to the gun trunnion axis in accordance with the height of the target, the guide thus acting as an eccentric upon the member carrying the sight.

According to the present invention the sighting apparatus is provided with a cam so designed that as the gun is elevated to keep the sight on the target the angle of tangent elevation is automatically altered both for the change of range and the change of angle of sight without its being necessary to ascertain the range. In this'manner as the height may (especially in the case of an airship) remain constant for an appreciable length of time notwithstanding constant alterations in the range, we avoid the necessity for con'- stantly varying the preliminary adjustment as the range increases or decreases, with the result that a consequent increase in the accuracy of fire and the rate of fire is obtained. Furthermore it becomes possible to control from a central station the adjustment of the sighting apparatus of any number of guns arranged at considerable distances apart since although the range of the target may be different at each of the guns, the height will naturally be the same.

In the preferred constructional form of our improved sighting apparatus, we employ a cam of the profile type whose position is adjustable to agree with the height of the target and against which bears a roller or projection carried by the sight arm, relative movement between the cam and roller being caused to take place during the elevation and depression of the gun to automatically alter the angle of tangent elevation as aforesaid. A

In order that the said invention may be clearly understood and readily carried into effect we will describe the same more fully with reference to the accompanying drawings, in which Figure l is a side elevation viewed from the left hand side of the mounting, showing more or less diagrammatically a constructional form of the improved sighting apparatus.

'F 1g. 2 is a view similar to Fig. l, but viewed from the right hand side of the mounting.

Fig. 3 is a view similar to Fig. 1 showmg, also more or less diagrammatically, a modified form of the sighting apparatus.

Fig. l is a view similar to Fig. l showing, also more or less diagrammatically, a further modified form of the sighting apparatus.

Fig. 5 is an end elevation on an enlarged scale of the cam and roller of Fig. 4.

Fig. 6 is a view similar to Fig. 5 showing a modified arrangement of the cam and roller, and

Fig. 7 is a plan view showing the relative positions of the component parts of the sighting apparatus and their connections on both sides of the gun.

A is the carriage and A the cradle. B is the sight arm pivoted at to a bracket on the cradle. b is the roller on the sight arm and B is the cam upon which the roller bears.

In the example shown by Figs. l and 2, the cam B is pivoted on a suitable pivot B2 attached to the left hand side of the carriage and is swung about this pivot, to agree with the height of the target, by a hand wheel b2 which is mounted at the right hand side of the mounting and which Operates through worm gearing upon a pinion b3 meshing with a segmental rack B3 iiXed to the cam B. The rotation of the handwheel b2 angularly displaces a graduated dial b4 so that the adjustment given to the cam can be read in terms of height of the target. After the cam B has been adjusted tothe desired position, the gun is elevated or depressed to bring the sight on the target and during this operation the roller b moves around the cam B and the required alteration to the angle of tangent elevation is automatically effected. In the example shown the sight arm carries a check roller Z/X engaging in a cam groove BX in the cam B.

The sight bar or carrier B4 on the left hand side of the cradle is connected by a deflection pivot b5 to an intermediate bar B5 pivoted to the sight arm B co-aXially with the pivot b. Interposed between the sight arm B and the intermediate bar B5 is suitable gearing operated by a handwheel be for elevating or depressing the sight in relation to the sight arm to effect vertical spotting corrections and interposed between the intermediate bar B5 and a rearward eX- tension of the sight bar is gearing operated by a handwheel t7 for deflecting the sight to effect lateral deflection and spotting corrections. The intermediate bar B5 is crossconnected to a bracket B6 on the right hand side of the cradle and the sight bar B7 on this side of the cradle is pivoted by a deflection pivot bs to the said bracket and is cross connected by a rod B8 to the rearward extension of the sight bar B4 on the left hand side of the mounting` A pointer C (see Fig. 2) may be provided which moves across the face of the dial b4 as the gun is elevated. rIhe face of the dial may be marked with curves giving the true range or equivalent time of flight or the fuse number for the particular height to which the dial has been adjusted, in conjunction with the angle of sight. The reading observed against the pointer may be used for the purpose of setting the shell fuses. The said pointer may form part of a link C pivoted at C2 to the cradle and formed with a slot engaging with a pin C3 on a bracket attached to the carriage.

The modified construction shown by Fig. 3 is similar to Figs. 1 and 2 except that the cam B is mounted on the cradle and is caused to move with respect to the gun through an angle equal to the angle of elevation of the gun, by a link b9 pivoted at its forward end to a bracket a on the carriage and at its rear end to an arm B9 pivoted at B2 to the cradle carrying the height setting gear. The link b9 and the arm B9 are so arranged that a parallel motion arrangement is provided for maintaining the cam B at a fixed angle in space during the elevation and depression of the gun, subject of course to any adjustment that may be given thereto by the hand wheel b2. The broken lines in Fig. 3 show the position of the cam when the gun is pointing at the maximum angle of elevation. Instead of the link b9 suitable gearing may be employed for obtaining the saine result. In this construction the check roller bx and the groove BX of Figs. l and 2 are not employed, the roller being held in firm contact with the cam by a spring operating on the sight arm.

In Figs. 4f to 6 a surface cam attached to the carriage is employed instead cf a profile cam as in Figs. l to 3 and in this case the adjustments for different heights instead of being effected by angularly displacing the cam is effected by causing relative lateral movement to occur between the roller b and the cam by a handwheel b2* so as to bring the roller on the lamination of the cam corresponding to the particular height of the target. In Figs. 4 and 5 the roller Z2 is moved across the cam and in Fig. 6 the cam is movable laterally with respect to the roller.

The cam of Figs. l and 3 may be so constructed as to also impart to the sight the correct angle of lead or vertical deflection for a targent advancing toward or receding from the gun position, allowing for the varying time of flight for the changing range. For this purpose the cam would be adjustable angularly for different heights as described with reference to Figs. l and 3,

.but instead of being of the profile type it would be of the surface type; the center lamination of the cam would correspond to no speed of the target and the laminations. to each side of this center lamination would correspond to targets advancing toward or receding from the gun position at different speeds, means being provided for effecting relative lateral movement between the roller and the cam to bring the desired lamination into use.

IV hat we claim and desire to secure by Letters Patent of the United States is 1. In sighting apparatus for anti-aircraft guns, the combination Qiasight/ and means for elevating and depressing the gun to keep the sight on the target, with means comprising a cam for automatically altering the angle of tangent elevation during the elevation and depression of the gun, for both the change of range and the change of angle of sight without ascertaining the range.

2. In sighting apparatus for anti-aircraft guns, the combination with the sight arm, of a cam upon which the sight arm bears, means for adjusting said cam in accordance with lthe height of the target and means for causing relative movement to take place be tween the sight arm and the cam during the elevation and depression of the gun so as to cause the cam to effect the required correction in the angle of tangent elevation.

3. In sighting apparatus for anti-aircraft guns, the combination with the sight arm mounted on the gun cradle, of a cam upon which the sight arm bears, and means for adjustably connecting said cam to the gun carriage so as to enable its position to be altered in accordance with the height of the target.

Il. In sighting apparatus for anti-aircraft guns, the combination with the sight arm,

of asurface cam upon which the sight arm bears, means for adjusting said surface cam in accordance with the height of the target and means for causing relative movement to take pla-ce between the sight arm andthe surface cani during the elevation and depression of the gun so as to cause the surface cam to elect the required correction in the angle oit' tangent elevation.

5. In sighting apparatus for anti-aircraft guns, the combination with the sight arm, of a surface cam, a roller on said sight arm for bearing upon said cam, means for effecting relative lateral movement between the roller and the cam to bring into operation the surface or lamination of the cam corresponding to the ascertained height of the target and means for causing the roller to travel in contact with said surface or lamination during the elevation and depression of the gun.

6. In sighting apparatus 'for anti-aircraft guns, the combination with a cam device capable of adjustment, to agree with the height of the target and serving during the elevation and depression oi the gun to automatically vary the angle of tangent elevation, of means actuated by said cam device for automatically indicating the true range of the target or equivalent time of flight of the projectile or the fuse number'.

7. In sighting apparatus Jfor anti-aircraft gun, the combination with a cam device capable of adjustment to agree with the height of the target and serving during the eleva-- tion and depression of the gun to automatically vary the angle of tangent elevation, of a member marked with curves, means for moving said member by the adjustment given to the cam device, a pointer, and means for causing said pointer to move across said member during the elevation and depression of the gun.

S. In sighting apparatus for anti-aircraft guns, a sight and means for imparting to the` sight the correct angle of lead or vertical deflection for a target advancing toward or receding from the gun, comprising a cam device adapted to be adjusted to agree with the height of the target and to serve during the elevation and depression of the gun to automatically vary the angle of tangent elevation.

9. In sighting apparatus for anti-aircraft guns, the combination with the sight arm, of a surface cam, a roller on said sight arm for bearing against the cam, means for angularly adjusting said cam to agree with the height of the target, and means for causing relative lateral movement to occur between the cam and the roller to agree with the speed of a target advancing toward or receding from the gun.

In testimony whereof we have hereunto aiiixed our signatures.

ARTHUR TREVOR DAWSON. GEORGE THOMAS BUCKHAM. Vitnesses:

JNO. L. CAswELL, GERTRUDE WHYTE. 

